Friction stir welds with enhanced fatigue strength and life via post-weld laser peening

Friction stir welding (FSW) has been studied as a viable solid state joining process for aircraft fuselage structures. As any other high temperature joining process, it introduces tensile residual stress fields and leads to microstructural changes in the structure which would adversely affect the performance of a joint. FSW may also introduce defects which would act as sites for fatigue initiation and propagation. Laser peening (LP) is being studied as an advanced and viable surface treatment option to introduce a compressive residual stress state in a fuselage structure which could potentially recover the fatigue life by preventing initiation and propagation of fatigue damage. The presentation will focus on fatigue crack – stress interaction in fuselage structures/joints subjected to fatigue loading and how designing of laser peening process is vital to achieve the necessary recovery of fatigue life.

Joana Antunes, Doctoral Researcher, Cranfield University